FIELD OF THE INVENTION
This invention relates to a starter clutch assembly, and, more particularly, this invention relates to a lubrication system for an overrunning starter clutch assembly.
Typically an overrunning type clutch is used in starter assemblies. The overrunning type clutch transmits torque in one direction and is freewheeling in the opposite direction. The starter requires a gear reduction from a conventional electric motor to produce the high starting torque necessary. When the engine starts, it instantaneously accelerates towards its running speed forcing the clutch to overrun with its output rotating faster than its input. In automotive engines, the starter is moved out of contact with the engine gear so that it only operates at the high engine speed for a very short period of time, allowing lubrication of the starter clutch to be accomplished by grease packing. In aircraft engines, the clutch output preferably continues to rotate at engine speed, making grease packing impractical. Thus, some kind of continuous lubrication is necessary.
In prior art starter clutches, engine oil has been introduced into the clutch unit and allowed to return to the sump through holes drilled in the sump housing and end clearances with no pumping action. This allows contaminants in the oil to be centrifuged out of the oil and become trapped inside the clutch unit contributing to a diminished service life.